Daily Water Intake Calculator

About this Water Intake Calculator

Hydration advice is often noisy. This calculator keeps it simple and practical. Enter your weight, daily activity, climate, and whether you are pregnant or breastfeeding. You will see a realistic daily target in liters and ounces, plus an easy view in 8-oz cups and your own bottle size. All math runs in your browser for speed and privacy. Nothing gets saved or sent anywhere.

For the baseline we use a common practical range of 30–40 mL per kilogram of body weight. Many healthy adults land near 35 mL/kg, so that is the default. We then add water for exercise based on time and intensity, adjust for heat and humidity with a simple percentage, and include flat daily adds for pregnancy and breastfeeding. It is a calculator, not a rule. You should still listen to your thirst, urine color, and how you feel through the day.

How to use

1. Select units. Choose U.S. (lb, fl oz) or Metric (kg, mL). The fields and hints switch to match.
2. Enter weight. Use your current body weight. The baseline target scales with kg.
3. Add activity. Enter average minutes per day and choose intensity. The tool adds roughly 8 oz per 30 minutes for light work, 12 oz for moderate, and 16 oz for intense sessions.
4. Adjust for climate. Pick +10% for hot or humid days, +20% for very hot or very humid days. If conditions change, update the selector.
5. Pregnancy & breastfeeding. If applicable, these add fixed amounts (about 300 mL and 700 mL per day).
6. Pick a bottle size. Enter your usual bottle to see “bottles per day.” This makes the target easier to hit.
7. Export. Use CSV to save your setup and totals. Handy for clients or training logs.

Understanding the results

The Summary table breaks down your baseline (based on mL/kg), exercise add (converted from ounces to mL), and climate add (a percentage of baseline plus exercise). If pregnancy or breastfeeding applies, those are shown as flat additions. The footer line shows the total per day in liters. On the right, you will see the same total expressed as 8-oz cups and bottles of your chosen size. If your number feels high on a rest day, lower the activity minutes or remove the climate add. If you are training hard or sweating heavily, bump the intensity or percentage and consider electrolytes for sessions beyond an hour.

This tool is not a medical device and is not meant to diagnose or treat any condition. People with kidney or heart disease, those on fluid-restricting medications, or anyone with unique medical needs should talk to a clinician for individual guidance.

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